At the end of season four last May, most of Jack Bauer's colleagues at L.A.'s Counter Terrorist Unit thought he'd been shot and killed. (Actually, he went into deep hiding over an unfortunate little dustup with the Chinese government.) But here he comes again, played by Kiefer Sutherland, eyes squinting, handweapon at the ready, like Clint Eastwood in the role of Lazarus. Good for America. In the four-hour kickstart to what looks to be a season of solid suspense, a high-level assassination flushed Jack out of hiding and sucked him back up into the show's latest sluicing black hole of conspiracy, murder and countdown to mass destruction (this time, it's biochemical). Jack was initially framed for the killing. But as the greasy smoke of many detonated bombs thinned, Jack's innocence became evident to CTU. Only how to explain away the fact that his face was caught on a security videotape, putting him within comfy shooting distance of the killing? By now, the show's star has pretty much perfected his scuffed, hardboiled loner act. The voice sounds like sandpaper against a brick. Jean Smart is new, as a First Lady prone to mental meltdowns, and she's good, wheeling about and gasping in panic. I wonder how Delta Burke would have been. And Mary Lynn Rajskub continues to add subtle realistic comedy as systems analyst Chloe O'Brian. She reacts to each development by scrunching her face, as if she'd just received an update on the progress of a tapeworm. Or a terrorist.